Merlin McFly head clearance tool
This is the fully CNC machined head clearance tool from the Merlin McFly factory. Made from high quality Swiss 7075 alloy, the part can be attached to any digital or analog dial indicator that features a Ø8mm shaft. The assembly is screwed into the combustion chamber and set to zero on a flat surface. Then the engine can be assembled back together with all necessary head shims. After this the tool is mounted a second time to check the head clearance by turning the engine to the top dead centre. The value that can be read on the digital/analog scale is your total head clearance.
Source: Merlin McFly [merlinmcfly.de]